Split air-conditioner in shop...

[ST1100Y]

Upon relocating to the "new" bike shop in '23, we soon found that its getting pretty hot in there during the summer; roof is made of prefabricated concrete slabs, sealed with Bitumen rolls...

So in '24 I came across a really decent offer for a 12,000Btu split-set, R32, infrared remocon, heat/cool... € 399,-... (despite working in that trade, I'd never gotten one that cheap at my workplace...)
Installation done in about 2 hours, 1/4" & 3/8" pipes, flare connections, interconnecting & supply cables, drawing vacuum, etc... (still got all the tools...)
So the summer was comfy and cool, 25°C and low humidity, with no issue... once it got colder in fall, depress HEAT, comfy again... and way more efficient then the electric blower heater...



Turns out it even features a "frost protection mode", fixing the set-temp to 8°C/46°F by depressing the ECO button for >5 seconds... cool!
To confirm what its actually doing there, I obtained a small temperature logger:



Working flawless!

 

[Obo]

Cool!

Well, at least half of the year.

 

[Fawlty]

Upon relocating to the "new" bike shop in '23, we soon found that its getting pretty hot in there during the summer; roof is made of prefabricated concrete slabs, sealed with Bitumen rolls...

So in '24 I came across a really decent offer for a 12,000Btu split-set, R32, infrared remocon, heat/cool... € 399,-... (despite working in that trade, I'd never gotten one that cheap at my workplace...)
Installation done in about 2 hours, 1/4" & 3/8" pipes, flare connections, interconnecting & supply cables, drawing vacuum, etc... (still got all the tools...)
So the summer was comfy and cool, 25°C and low humidity, with no issue... once it got colder in fall, depress HEAT, comfy again... and way more efficient then the electric blower heater...



Turns out it even features a "frost protection mode", fixing the set-temp to 8°C/46°F by depressing the ECO button for >5 seconds... cool!
To confirm what its actually doing there, I obtained a small temperature logger:



Working flawless!

Yes. These inverter units are surprisingly economical to run all year round.

 

[motornut]

My son is in the HVAC business too. He had been pestering us for years to put in a mini split system for our house. We finally did and there is no chance of going back to the old window shaker system. I have a shop that I airbrush in and needs the heat to keep paint from freezing, I like it more in the summer than the winter for temp. They work awesome!!!!!!!

 

[MaxPete]

Upon relocating to the "new" bike shop in '23, we soon found that its getting pretty hot in there during the summer; roof is made of prefabricated concrete slabs, sealed with Bitumen rolls...

So in '24 I came across a really decent offer for a 12,000Btu split-set, R32, infrared remocon, heat/cool... € 399,-... (despite working in that trade, I'd never gotten one that cheap at my workplace...)
Installation done in about 2 hours, 1/4" & 3/8" pipes, flare connections, interconnecting & supply cables, drawing vacuum, etc... (still got all the tools...)
So the summer was comfy and cool, 25°C and low humidity, with no issue... once it got colder in fall, depress HEAT, comfy again... and way more efficient then the electric blower heater...



Turns out it even features a "frost protection mode", fixing the set-temp to 8°C/46°F by depressing the ECO button for >5 seconds... cool!
To confirm what its actually doing there, I obtained a small temperature logger:



Working flawless!

I put a mini-split in my 800 sf. (about 80 sq. meters) pole barn / workshop over the summer of 2024. It is a 24,000 BTU (that's two tons of cooling) Mitsubishi heat pump / AC minisplit. Coupled with the four zone gas-fired heated floor, it is always toasty warm in the winter and nice and cool in the summer.

The heated concrete floor is so efficient that it maintains the barn at 60 deg. F (about 15-16C) in the winter and, while I know the system does run occasionally, my wife tells me that the effect on our heating bill has been negligible over the last two winters.

The boiler for the heated floor is neat white metal cabinet about 2 ft high x 18" wide x about 10" deep (around 60 cm high x 45 cm wide x 25 cm deep) and is mounted on the wall at about eye level with the thermostat beside it. Thus, the floor is likely heated above 60 deg. F because the thermostat is mounted about 5 ft. off the floor. The boiler/pump unit is virtually silent - you really have to listen carefully to hear it running. Granted, the barn is very well insulated and the doors seal well, but it truly is a great system and I have had zero problems with it for more than two years. In fact, I haven't even opened the cabinet to look inside since it was installed.

As for the mini-split AC/heat pump, the only time it comes on in the winter is if I open the overhead door and cold air rushes in. The unit clicks on and warms the air back up to around 63 deg. F and then it shuts off and the heated floor maintains the temp 24/7. It is also extremely quiet and has a remote controller with very extensive programmability features. The louvers can pivot to distribute cool or warm air all over the barn.

In my experience, 60 deg. F / 15C would be a tad chilly if I was sitting around reading a book but as I am up, walking around, using tools, bending and stretching, it is fine - shirt sleeve comfort in there and my feet do not get cold at all.

 

[Andrew Shadow]

The heated concrete floor is so efficient that it maintains the barn at 60 deg. F (about 15-16C) in the winter and, while I know the system does run occasionally, my wife tells me that the effect on our heating bill has been negligible over the last two winters.

Same here. I put in a heated concrete floor in my garage, heated by electric heating cables. The first winter I kept the thermostat at 12°C/54°F because I didn't know what effect it would have on my electricity bill. It was cool if you were in there doing something. Last winter I left it at 16°C/61°F all the time. It is plenty warm enough if I am in there doing something and I haven't noticed any appreciable difference to my electricity bill. Once that mass of concrete is warmed up it takes very little energy to keep the temperature stable. The good thing about a heated floor is that the heat remains fairly stable up to about five feet above the floor and above five feet the temperature begins to drop off. This is perfect because we spend all of our time within about six feet of the floor. I also never have to kneel or lay on a freezing cold and damp concrete floor anymore. Another benefit is that the piece of the concrete floor that extends outside of the garage door always melts the snow and ice off of it and then it dries off. I never have a garage door frozen to the ground anymore.

 

[milq]

I regret not putting in the floor heat in my shop! It was a significant bump in cost, I had been putting off the build for 3 years and just didn't want to wait any longer.

 

[ChucksKLRST]

When we remodeled the kitchen and master bath we had electric heated floors installed. Feels great on the feet in the middle of the night on a midnight snack run, or a bathroom pit stop. Been working good now for 15 years.

 

[MidLife]

So in '24 I came across a really decent offer for a 12,000Btu split-set,

How many m2 are you covering with these 12000 BTUs (ASHRAE BTUs?)?

 

[ST1100Y]

Yes. These inverter units are surprisingly economical to run all year round.

On an air-to-air with a COP of 4 and more, you'll get over 4000W heating at less then 1000W input...
That 3-phase 5kW electric blower will only give like 4900W effectively...

How many m2 are you covering with these 12000 BTUs (ASHRAE BTUs?)?

The shed has about 36m²/380sq ft, and since its a shop and not office space/living room it works out quite well...
Having 25°C instead of >36°C in the summer, and maintaining 8°C plus raising >15°C within an hour instead of freezing temps during the winter is quite OK...

 

[Chris09]

[edited] realizing a COP of 4:1 might happen on the verge of a heating requirement; but more often than not, by the time any modern structure needs heat, the OAT won't be high enough to achieve that, and as the outdoor temperature drops and the heating requirement rises, it becomes the net sum of diminishing returns. Compounding that is the more often than not poor location of the outdoor unit, whether it be partially concealed or in proximity to other units. A lot of buildings have multiple outdoor units located in a common parkade area, usually on the first or second level where there is limited but, at least some overall ventilation, or in close proximity on a limited roof area. In these situations, the outdoor units will [for lack of a better] "gulp up" each other's cold air and kill that COP capability. When the outdoor units are grouped in parkades there are sometimes Air Transfer Fans that force away or spread the cold air [or the heat of rejection in the summer].
In and of themselves, all of these new units are very impressive; lasting around fifteen years or better. Indoor units become condemned often on the basis of cost of replacement blower motors whereas outdoor units usually get exchanged when a compressor fails. Since R410A, I'm aware of few coil or condenser failures. Our recycle bin is usually filled with units that are at least fifteen years old now which I think isn't bad.

 

[ST1100Y]

realizing a COP of 4:1 might happen on the verge of a heating requirement; but more often than not, by the time any modern structure needs heat, the OAT won't be high enough to achieve that, and as the outdoor temperature drops and the heating requirement rises, it becomes the net sum of diminishing returns.

Actually ambient humidity impacts COP the most...
Highest correction factors apply between +2 to +7°C (35 to 45°F) when the kit has to go into defrost more frequently, hence less continuous heating performance per hour...
At like -5 to -10°C (23 to 14°F) the ambient air is so dry again, that the kits show better performance numbers as during "warmer" temperatures shown above...

Compounding that is the more often than not poor location of the outdoor unit whether it be of itself or in proximity to other units.

Well, installer (or sales) errors are always an issue... as are client's demands (insisting on "invisible" air-conditioning)...
Or (noise) complaints by neighbors, requiring CDUs being housed in, blocking the airflow...
And "monument protection acts" in old city centers, causing kits to get located out of sight in basements or attic spaces...
Also hilarious when they wall mount several a2a heat-pumps on top of each other, so when one defrosts it'll soak the ones below...
Or ignoring drainage in public areas, causing a glacier growing across the path in a courtyard... -> liability issues...

 

[Chris09]

Well you're clearly in the reality of the situation; I can only imagine that's it's one that concerns you, however when you reference correction factors, I gotta be honest, I wouldn't look out the window to dignify a great deal of it... by now... maybe some of it is legit...
Good song I learned when I was young; "nothing from nothing leaves nothing... leaves... nothing... gotta have something... there was a three lyric ending to that song,
Sad part is that these units that work very well, never work out well. They gotta breathe.

 

[Williamson]

Big fan of the reverse cycle / split systems here.

We put a very large Fujitsu split system in our old house back in 2016, continues to work faultlessly for no.2 son and family, followed it up with solar panels. Cheap to run, the solar panels provide enough input to keep the house cool on our 40C summer days, and warm on 0C winter mornings, providing the sky is clear, overcast and / or wet days are a different matter.

We have downsized to a townhouse, the builder installed 6 Fujitsu split systems, one in each bedroom and each living area. Haven't had them all operating at the same yet, probably never will. Although electricity bills are not to high, I will get some solar panels installed. Our state government (probably other states too) offer some pretty generous subsidies. Don't recall what the actual $$ figure was, but I think the system at the old house set us back round AU$3K, given the current exchange rate, that'd be around US$2K.

Yeah, big fan.

 

[Andrew Shadow]

I think that heat-pumps are a great invention and have not seen any down-side to having one installed. I would think that a heat-pump is all that would be needed in many areas of the world that don't have the cold winters that we have here in Canada. I have a whole house heat-pump that was installed in 2008 that ran on Freon R22. I never had a problem with and it and it reduced our heating costs tremendously in addition to giving us air conditioning. Last summer it sprung a leak. Since R22 is no longer available it had to be filled with R438A which, from what I understand, is designed to be a retrofit gas for old R22 units. It works fine however, while the air conditioning seems to be just as good, it is no longer as efficient in heating mode as it was when it was running on R22. I was told in advance that this would be the case and that this is what most people experienced after doing this. R438A in was a lot cheaper than getting a whole new unit however. Even though it is 17 years old it still works very well.

There are heat-pumps on the market now that are rated at -30°C. When it comes time to replace mine this is what I will be installing. Apparently a lot of people are now using them as their only source of heating. Even in our cold Canadian winters they no longer have a back-up heat source to support the heat-pump. Maybe by the time that I need a new one they will be rated down to temperatures even colder than that so that there will be an even bigger buffer between the rating and reality.

As good as I think that heat-pumps are, and I would not be without one, unfortunately they can't give you that nice feeling that you get when the big old oil-burning beast in the basement fires up and blasts out 145°F hot air. That comes at a price though.

 

[Chris09]

I shouldn't corelate R410A with fewer leaks than R22 but I think it's in and around the period where 410A arrives where the quality gets a little better. The Daikins Fujitsu and Mitsubishis LGs and host of other whole new wave manufactures on the residential light commercial side seem to have better designed coils. R410A pressures are a fair bit higher than R22 as well so that had to work. I was still able to buy R22 late last summer. I believe in Canada you can still buy reclaimed R22 through the wholesalers. There's a variety of R22 retrofits available that are comparable in performance and compatible with mineral or AB or whatever oil is in the system. Gone are the three oil changes, blends and the temperature glides. I think the last time I used one was for a couple pool dehumidifiers, something 99. Worked well.
In the instances of close proximity and so on, these locations that I'm citing are not determined by the installer [new buildings towers mostly]. The reality is there are so many considerations and constraints that good locations simply don't exist. Theft vandalism and esthetics. Even on six and seven story roofs units are grouped in close proximity with a perimeter fence.
I'm not entirely surprised to hear that in higher wet bulb conditions some units use more energy run worse; but there's more heat in wet air, that should increase the COP. I thought those were old heat pump problems combined with no electric heating stages for back up. Will have to look into that one.
Even with the higher rated units, I would still not be without electric second or third stage back up in colder climates.
Getting someone to procure and change a compressor in minus 20 or 30 might take some number of days.

 

[Bmacleod]

Theft vandalism and esthetics. Even on six and seven story roofs units are grouped in close proximity with a perimeter fence.

Yet another good argument for (cheap) R290, and yet politicians refuse to allow it in North America.

 

[ST1100Y]

I shouldn't corelate R410A with fewer leaks than R22 but I think it's in and around the period where 410A arrives where the quality gets a little better.

You guys are like a quarter century behind...
R22 fade out happened in the 90ies, R410A is frowned upon/faded out over its GWP, even the current R32 is on the brink/fade out, R290 advertised as "the future" by the environmentalists...
That Asia, Africa and probably South America still use R22 is a different, well concealed issue...

 

[mortenk]

I love heat pumps and mini split systems - have installed about a dozen by now. I just bought a heat pump based water heater that I plan to install this weekend. Curious to see how well they work and what it'll do to my bills.